What is "rollover" in fire behavior?

Rollover refers to a specific condition in fire behavior where unburned gases in the upper layer of a compartment ignite and spread across the ceiling or upper area of the room. This phenomenon is often referred to as flameover, as it typically occurs when the combustibles in the fire area have reached their ignition temperature and produce enough heat to ignite the layer of gas above.

In this context, flameover is characterized by the rapid combustion of these gases, which can quickly increase the fire's intensity and pose significant dangers to anyone in the vicinity. Understanding rollover is crucial for fire investigators and responders, as it can lead to flashover, a more dangerous event where everything in the room ignites almost simultaneously.

The other options describe different fire behavior processes. The transition of fire to a less hazardous state does not align with the nature of rollover, which signifies an increase in hazard due to ignition of flammable gases. A significant reduction of energy release also does not relate to rollover, as rollover involves an increase in energy release due to the ignition of gases. Lastly, the process of flame self-extinguishing contradicts the very essence of rollover, which centers on flames spreading and intensifying the fire behavior. Therefore, flameover accurately captures the essence of